Waste heat utilization system of slag powder hot blast stove

Abstract

The utility model discloses a slag powder hot-blast stove waste heat utilization system which comprises a mixing tank used for mixing circulating air and hot smoke and a hot-blast stove provided with an interlayer on the side wall and outputting the hot smoke, the interlayer of the hot-blast stove is communicated with an interlayer fan, and the interlayer fan is used for blowing air into the interlayer to generate preheating air. The mixing tank is communicated with a waste heat flue gas conveying pipeline, the waste heat flue gas is used for replacing part of circulating air, the interlayer of the hot blast stove is communicated with another waste heat flue gas conveying pipeline, and the other waste heat flue gas is used for replacing the interlayer fan to blow air into the interlayer. The problem that in the prior art, a vertical mill drying system needs to consume a large amount of blast furnace gas, and consequently the slag powder preparation cost is high is solved.

Description

Technical Field

[0001] This utility model relates to the field of slag powder preparation technology, specifically to a waste heat utilization system for a slag powder hot blast stove. Background Technology

[0002] Blast furnace slag is a byproduct of the ironmaking process in blast furnaces. During ironmaking, iron oxide is reduced to metallic iron at high temperatures. Impurities such as silica and alumina in the iron ore react with lime and other materials to form a molten substance mainly composed of silicates and aluminosilicates. After quenching, this molten substance becomes a loose, porous granular material, which is blast furnace slag, or simply slag. After grinding, the slag forms slag powder, also known as granulated blast furnace slag powder. This powder is a high-quality concrete admixture that can improve the strength of concrete after curing.

[0003] In existing slag powder grinding processes, a large amount of hot air is required to dry the blast furnace slag. This hot air is primarily obtained by heating air using blast furnace gas as fuel. However, the high temperature generated by blast furnace gas combustion necessitates cooling. Therefore, the high-temperature flue gas from blast furnace gas combustion needs to be mixed with preheated air in the hot blast stove jacket and also with self-circulating air. However, the temperatures of the existing preheated air and self-circulating air are relatively low, requiring a high flow rate of blast furnace gas combustion to maintain the temperature of the flue gas entering and leaving the mill. This results in a temperature as high as 14,000–15,000 m³ / h. 3 The consumption of blast furnace gas per hour increases the cost of slag powder preparation. Utility Model Content

[0004] The purpose of this invention is to solve the problem that the existing vertical mill drying system requires a large amount of blast furnace gas, resulting in high costs for slag powder preparation, and to provide a slag powder hot blast stove waste heat utilization system.

[0005] To address the shortcomings of the aforementioned technical problems, the present invention adopts the following technical solution: a waste heat utilization system for a slag powder hot blast stove, comprising a mixing tank for mixing circulating air and hot flue gas, and a hot blast stove with a jacketed side wall that outputs hot flue gas. The jacketed side wall of the hot blast stove is connected to a jacketed fan, which blows air into the jacket to generate preheated air. The mixing tank is connected to a transmission pipe for waste heat flue gas, which is used to replace part of the circulating air.

[0006] The hot air furnace has an interlayer connected to another waste heat flue gas transmission pipe, which is used to replace the interlayer fan blowing air into the interlayer.

[0007] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: a second valve is provided on the transmission pipeline of the waste heat flue gas connected to the mixing tank.

[0008] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: a third valve is provided on the waste heat flue gas transmission pipeline connected to the jacket of the hot blast stove.

[0009] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: a first valve is provided on the circulating air input transmission pipeline.

[0010] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: the temperature of the waste heat flue gas is greater than 160℃.

[0011] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: the hot blast stove is supplied with combustion air and blast furnace gas.

[0012] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: the output end of the hot blast stove is connected to the bottom of the mixing tank, the bottom of the mixing tank receives circulating air on one side, and the upper two sides of the mixing tank output the flue gas entering the mill.

[0013] As a further optimization of the waste heat utilization system of the slag powder hot blast stove of this utility model: the top of the mixing tank is connected to the waste heat flue gas pipeline.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] This invention connects the mixing tank and the hot blast stove to waste heat flue gas transmission pipelines with a temperature greater than 160°C. This allows for the proportional replacement of some of the circulating air and the air blown into the hot blast stove jacket by the jacketed fan. This reduces the temperature consumed in generating hot flue gas and milling flue gas at the corresponding temperatures, thus significantly reducing the amount of blast furnace gas used. Consequently, the cost of drying slag can be greatly reduced, thereby lowering the cost of preparing slag powder. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the connection structure of this utility model;

[0017] The markings in the diagram are: 1. Waste heat flue gas; 2. Flue gas entering the mill; 3. Circulating air; 4. Mixing tank; 5. Hot flue gas; 6. Preheating air; 7. Jacket fan; 8. Combustion air; 9. Blast furnace gas; 10. Hot blast stove; 11. First valve; 12. Second valve; 13. Third valve. Detailed Implementation

[0018] To better understand this utility model, the following embodiments further illustrate the content of this utility model, but the content of this utility model is not limited to the following embodiments.

[0019] like Figure 1As shown, a waste heat utilization system for a slag powder hot blast stove, similar to existing technologies, includes preheating air 6 input to the side wall of the hot blast stove 10, blast furnace gas 9 and combustion air 8 inside the hot blast stove 10. The blast furnace gas 9 is first mixed and burned with the combustion air 8 to generate hot air at 1000°C, and then the gas is cooled to about 90°C with a blowing volume of about 70,000 m³. 3 The preheated air 6 is mixed with the blast furnace gas 9 after combustion. Specifically, the preheated air 6 is delivered by the jacket fan 7 into the jacket of the hot blast stove 10 and mixed with the blast furnace gas 9. Subsequently, hot flue gas 5 with a mixed temperature of about 600℃ is generated, and the hot flue gas 5 is fed into the mixing tank 4 to mix with the gas inside the mixing tank 4, which has a flow rate of 140,000 m³ / h. 3 The self-circulating air 3 at a temperature of 80℃ is mixed with the slag, and then the flue gas 2 at a temperature of about 300℃ is generated to enter the vertical mill from the air ducts on both sides of the vertical mill to dry the slag.

[0020] The output end of the hot air furnace 10 is connected to the bottom of the mixing tank 4. The circulating air 3 is output by the circulating air 3 machine, and the circulating air 3 is input from one side of the bottom of the mixing tank 4 to rotate inside the mixing tank 4, thereby fully mixing with the hot flue gas 5 output by the hot air furnace 10. The mill flue gas 2 is output from both sides above the mixing tank 4, so that the hot flue gas 5 and the circulating air 3 are fully mixed and a stable temperature output is maintained.

[0021] Unlike existing technologies, the jacket of the hot blast stove 10 is connected to a waste heat flue gas 1 transmission pipe with a temperature greater than 160°C. The transmitted waste heat flue gas 1 is used to replace the preheating air 6 generated by the jacket fan 7 blowing air into the jacket of the hot blast stove 10. This will reduce the amount of heat required for the blast furnace gas 9 to be combined with the combustion air 8 to generate high heat. That is, it can generate hot flue gas 5 with the corresponding temperature and flow rate for use while reducing the input flow rate of blast furnace gas 9, thereby reducing the amount of blast furnace gas 9 used to a certain extent. The mixing tank 4 is filled with waste heat flue gas 1 with a temperature greater than 160°C to increase the temperature of the circulating air 3. Then, while maintaining the temperature of the flue gas 2 entering the mill, the input flow rate of hot flue gas 5 will be reduced, thereby further reducing the input flow rate of blast furnace gas 9.

[0022] A third valve 13 is provided on the transmission pipeline of the waste heat flue gas 1 into the hot blast stove 10. The setting of the third valve 13 makes it easy for the staff to adjust the flow rate of the waste heat flue gas 1 into the hot blast stove 10, and thus reduce the consumption of blast furnace gas 9 while maintaining the temperature of the output flue gas 2 based on the temperature of the introduced waste heat flue gas 1.

[0023] The top of the mixing tank 4 is connected to another waste heat flue gas 1 transmission pipe, and a second valve 12 is installed on the other waste heat flue gas 1 transmission pipe. The second valve 12 allows the operator to control the flow rate of the corresponding waste heat flue gas 1 into the mixing tank 4 according to specific circumstances. A first valve 11 is installed on the transmission pipe of the circulating air 3. The first valve 11 allows the operator to close the first valve 11 as needed, thereby adjusting the ratio of waste heat flue gas 1 replacing the input circulating air 3 in conjunction with the second valve 12. This allows the temperature of the flue gas 2 entering the mill to be maintained. This further reduces the amount of blast furnace gas 9 used, thereby lowering the cost of slag powder preparation. Correspondingly, the waste heat flue gas 1 is input from the top of the mixing tank 4, and the relatively low temperature of the waste heat flue gas 1 will sink to fully mix with the hot air and circulating air 3. Moreover, the higher temperature air after mixing will rise to stably output the mill flue gas 2 from both sides of the mixing tank 4. Thus, while reducing the amount of blast furnace gas 9 used, the temperature output of the mill flue gas 2 is maintained. At the same time, inputting from the top of the mixing tank 4 makes it easier for staff to build the corresponding pipeline path, which is convenient for staff to optimize the equipment.

[0024] In practical use, firstly, based on the specific factory operation conditions, select appropriate equipment capable of generating waste heat flue gas 1 at a temperature greater than 160°C, and construct transmission pipelines connecting to the hot blast stove 10 and mixing tank 4. Then, based on the specific temperature of the discharged waste heat flue gas 1, control the second valve 12 and the third valve 13, i.e., control the flow rate of waste heat flue gas 1 into the mixing tank 4 and hot blast stove 10. Afterwards, combustion air 8 and blast furnace gas 9 can be introduced into the hot blast stove 10 and burned at the center of the hot blast stove 10 to heat the air and generate hot air at 1000°C. Subsequently, the waste heat flue gas 1, i.e., preheated air 6, passing through the jacket of the hot blast stove 10, mixes with the 1000°C hot air. The mixture will then generate 600°C hot flue gas 5. During the mixing process, the higher temperature of the waste heat flue gas 1 will reduce the flow rate of the combustion air 8 and blast furnace gas 9. The hot flue gas 5 will then enter the mixing tank 4 and mix with the circulating air 3 and the waste heat flue gas 1 entering the mixing tank 4. During this process, the waste heat flue gas 1 will participate in the mixing, reducing the flow rate of the hot flue gas 5 and outputting 300°C inlet flue gas 2 to dry the slag with hot air. This reduces the mixing flow rate of the preheating air 6 and the 1000°C hot air, thereby reducing the flow rate of the combustion air 8 and the blast furnace gas 9, and thus reducing the cost of drying the slag.

[0025] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this utility model.

Claims

1. A waste heat utilization system for a slag powder hot blast stove, comprising a mixing tank (4) for mixing circulating air (3) and hot flue gas (5) and a hot blast stove (10) with a jacketed sidewall and outputting hot flue gas (5), wherein the jacketed sidewall of the hot blast stove (10) is connected to a jacketed fan (7), the jacketed fan (7) being used to blow air into the jacket to generate preheated air (6), characterized in that: The mixing tank (4) is connected to a transmission pipe for waste heat flue gas (1), which is used to replace part of the circulating air (3). The hot air furnace (10) has an interlayer connected to a transmission pipe for another waste heat flue gas (1), which is used to replace the interlayer fan (7) blowing air into the interlayer.

2. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: The mixing tank (4) is connected to the transmission pipeline of the waste heat flue gas (1) by a second valve (12).

3. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: A third valve (13) is provided on the waste heat flue gas (1) transmission pipeline connected to the jacket of the hot air furnace (10).

4. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: The circulating air (3) input transmission pipeline is equipped with a first valve (11).

5. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: The temperature of the waste heat flue gas (1) is greater than 160°C.

6. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: Combustion air (8) and blast furnace gas (9) are introduced into the hot blast stove (10).

7. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: The output end of the hot air furnace (10) is connected to the bottom of the mixing tank (4). Circulating air (3) is input on one side of the bottom of the mixing tank (4), and the flue gas (2) is output from both sides above the mixing tank (4).

8. The slag powder hot blast stove waste heat utilization system as described in claim 1, characterized in that: The top of the mixing tank (4) is connected to the waste heat flue gas (1) pipeline.

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